1. Field of the Invention
The present invention relates to cable terminations and more particularly to locking cable terminations which snap into place and require no screws or twisting for locking.
2. Related Prior Art
There has been an extensive number of various types of cable connectors that have been designed since the initial use of electricity prior to the turn of the century. Many types are still in use in some form. The most common initial design that is in use today is a form that was first patented in the mid-twenties. This form includes a screw that is tightened once the cable or electrical wire is in place. The electrical cable is fed into a hole or slot in a junction box through an oversized fitting that has provision for receiving a screw. In the early design the screw was configured to press directly against the electrical cable. This presented problems with the screw penetrating the insulation covering on the wire.
Presently, the screw type securement is one where the screw tightens a clamp that presses against the wire covering. The screw is normally fitted into the wall of a junction box and pulls the clamp closer to the wall as the screw is tightened. These clamps are designed so that even at their tightest when the screw pulls a portion of the clamp against the wall, there is a space between the portion of the clamp pressing against the wire and the wall of the junction box. In more recent years, there have been several patents that involve snap type fittings, of which the following patents are representative.
U.S. Pat. No. 3,858,151, titled "Flexible Conduit Connector", issued to J. H. Paskert, relates to a connector for securing a helically grooved flexible electrical conduit with a junction box that is formed as a one piece metal clip. The clip has a tubular body with tabs and barbs which engage the helical groove in the conduit to prevent the conduit from being pulled out of the clip and to electrically interconnect the clip conduit. The barbs and tabs are disposed along a common helical path to facilitate turning or screwing of the clip onto one end of the conduit. A collar on the inner end of the clip encloses the end of the conduit to protect wires in the conduit against engagement with any burrs which may be formed on the end of the conduit. Resiliently deflectable retaining arms and flanges clampingly engage a wall of the junction box to hold the clip and conduit in place. The retaining arms are provided with pointed end portions which are pressed against the wall of the junction box to electrically interconnect the clip and junction box.
U.S. Pat. No. 4,012,578, titled "One Piece Connector For Flexible Conduit", issued to T. M. Moran et al., relates to a one piece connector clip for securing a helically grooved flexible electrical conduit within generally round apertures in a junction box. The body of the clip comprises a plurality of generally flat sides and is provided with tabs which engage the helical groove in the conduit to prevent the conduit from being pulled out of the clip and to electrically interconnect the clip and conduit. A collar on the inner end of the clip encloses the end of the conduit to protect the wires contained therein against any burrs which may be present on the end of the conduit. Resiliently deflectable retaining arms and flanges clampingly engage a wall of the junction box to hole the clip and conduit in place and to electrically interconnect the clip and the junction box. In one embodiment of the invention, the body of the clip has a generally square cross-sectional configuration, in another embodiment, the body has a genally truncated equilateral triangular shape, while in still another embodiment the body has a generally hexagonal shape.
U.S. Pat. No. 4,880,387, titled "Connector For Flexible Electrical Conduit", issued to Allan Stikeleather et al., relates to a connector for joining flexible electrical conduit to a housing such as a junction box, fixture or the like which is formed cylindrically from light metal and includes relatively flexible arms depending from a relatively stiff face portion, retaining members flaring from the extending for a substantial portion of the length of the flexible arms. Multiple barbs are formed on the flexible arms to engage the conduit and flanges are formed at the extremity of the flexible arms to cooperate with the retaining members to clamp the connector to the housing.
U.S. Pat. No. 5,422,437, titled "Electrical Connector Assembly", issued to Kenneth Schnell, relates to an electrical connector assembly for coupling non-metallic electrical connector assembly includes a snap nut adaptor with an annular groove at one end forming a first mating member, and a conduit connector with resilient latch tabs forming a second mating member. Upon inserting the snap nut adaptor through a hole or knockout opening in an electrical box, the conduit connector is securely coupled thereto by inserting it over the snap nut adaptor until the latch tabs engage the annular groove via a snap fit.